Easing server load with message queues

Modern database backed web applications can handle many thousand reads per second with smart caching features, but what would happen if you suddenly experience a surge of users hitting sign up functionality which can't be cached?

Message queue are a great way to add padding into your system architecture in order to cope with unexpected traffic spikes.

User sign-up functionality can often take a considerable length of time, especially when many tables and foreign keys are involved.

Instead of creating user data immediately, send the validated form data into a message queue and instruct the user to check their email for a validation email. Meanwhile, your Create User functionality has been triggered by the event queue and is asynchronously performing the data tasks, finalising with the email to the user.

This is a good example of where your system doesn't immediately need to action the task and can return the user to a working state while the data layer continues in the background. This gives end-users a much snappier feel for your application.

Most message queue providers guarantee message delivery. As long as the data isn't removed from the queue, it will remain there.